Look at thredds_crawler

[dopplershift]

So I was pointed at this at SciPy:

https://github.com/asascience-open/thredds_crawler

We should at the very least look at what functionality they have and see what would make sense to add to Siphon. We might want to see about joining forces, but the sticky issue would be that their code is licensed under GPLv2.